kanji/readings_index/lesungen_script

#!/bin/bash
if [ -n "$1" ]; then
	printf "start at reading no. L-"
	read -r start_no
else
	last_line="$(tail -n1 readings_index)"
	echo "$last_line"
	start_no="$( echo "$last_line" | cut -f3)"
fi
for ((n=start_no;n<=4000;n++)); do
	printf "index of reading no. L-%s:" "$n"
	read -r index
	if [ "$index" = "" ]; then
		continue
	elif [ "$index" = "d" ]; then
		echo "deleting last line"
		grep -v "$(tail -n1 readings_index)" readings_index > tmp$$
		mv tmp$$ readings_index
		tail -n1 readings_index
		n="$(( n - 2 ))";
	elif [ "$index" -gt 0 ]; then
		line="$(grep -P "^$index\t" lesungen)"
		printf '%s\t%s\n' "$line" "$n" | tee -ai readings_index
	elif [ "$index" -eq 0 ]; then
		n="$(( n - 2 ))";
	fi
done